Huawei

About: Huawei is a company organization based out in Shenzhen, China. It is known for research contribution in the topics: Terminal (electronics) & Signal. The organization has 41417 authors who have published 44698 publications receiving 343496 citations. The organization is also known as: Huawei Technologies & Huawei Technologies Co., Ltd..

Bridge forwarding method and apparatus

Abstract: A bridge forwarding method comprises: receiving a frame from an input port, obtaining the input VLAN ID and a destination MAC address of the frame; determining an output port and an output VLAN ID of the frame, and forwarding the frame according to the output port and the output VLAN ID. A bridge forwarding apparatus includes at least one output port used for receiving a frame from more than one VALN, at least one output port used for transmitting the frame to more than one VALN and a forwarding unit, the forwarding unit obtains the input VLAN ID and the destination MAC address in the frame, determines the output port and the output VLAN ID of the frame, and outputs the frame to the corresponding output port. The method and the apparatus of this invention can realize the bridge forwarding of the Ethernet frames between multiple VLANs.

High- $Q$ Narrowband Tunable Combline Bandpass Filters Using MEMS Capacitor Banks and Piezomotors

Abstract: This paper presents the design and implementation of a new class of evanescent tunable combline bandpass filters based on electronic tuning with the use of RF microelectromechanical systems (RF-MEMS) capacitor banks and also mechanical tuning using piezomotors The use of microelectromechanical systems tuning circuit results in compact implementation of the proposed filters with high-Q and near to zero dc power consumption The proposed filter structures consist of combline resonators with tuning disks that are either mechanically moveable using piezomotors or are loaded with RF-MEMS capacitor banks Two- and six-pole tunable bandpass filters are designed and measured based on the proposed tuning concept The two-pole tunable filter operates at 25 GHz with a bandwidth of 22 MHz and demonstrates a tuning range of 110 MHz, while the quality factor is better than 374 (1300-374 over the tuning range) The six-pole tunable filter with RF-MEMS capacitor banks operates from 2634 to 259 GHz (44-MHz tuning range) The proposed tunable filter structures can also be implemented using alternative technologies such as barium-strontium-titanate varactors

Expanding LTE network spectrum with cognitive radios: From concept to implementation

Abstract: Wireless data traffic is growing extraordinarily, with new wireless devices such as smartphones and bandwidth-demanding wireless applications such as video streaming becoming increasingly popular and widely adopted. Correspondingly, we have also witnessed the phenomenal wireless technology evolutions to support higher system capacities from generation to generation. Long Term Evolution has been developed as a 4G wireless technology that can support next generation multimedia applications with high capacity and high mobility needs. However, the peak data rate from 3G UMTS to 4G LTE-Advanced only increases 55 percent annually, while global mobile traffic has increased 66 times with an annual growth rate of 131 percent between 2008 and 2013. Clearly, there is a huge gap between the growth rate of the new air interface and the growth rate of customers? needs. A promising way to alleviate the contention between the actual traffic demands and the actual system capacity growth is to exploit more available spectrum resources. Recently, cognitive radio technology has been under extensive research and study. It aims to provide abundant new spectrum opportunities by exploiting underutilized or unutilized spectrum opportunistically. In this article, we discuss the technical solutions to expand LTE spectrum with CR technology (LTE-CR), and survey the advances in LTE-CR from both research and implementation aspects. We present detailed key technologies that enable LTE-CR in the TV white space (TVWS), and related standards and regulation progresses. To demonstrate the feasibility of deploying LTECR in TVWS, we have conducted extensive system-level simulations and also developed a LTE-CR prototype. Both simulation and laboratory testing results show that applying LTECR in TVWS can achieve satisfactory performance.

On handling indicator constraints in mixed integer programming

Abstract: Mixed integer programming (MIP) is commonly used to model indicator constraints, i.e., constraints that either hold or are relaxed depending on the value of a binary variable. Unfortunately, those models tend to lead to weak continuous relaxations and turn out to be unsolvable in practice; this is what happens, for e.g., in the case of Classification problems with Ramp Loss functions that represent an important application in this context. In this paper we show the computational evidence that a relevant class of these Classification instances can be solved far more efficiently if a nonlinear, nonconvex reformulation of the indicator constraints is used instead of the linear one. Inspired by this empirical and surprising observation, we show that aggressive bound tightening is the crucial ingredient for solving this class of instances, and we devise a pair of computationally effective algorithmic approaches that exploit it within MIP. One of these methods is currently part of the arsenal of IBM-Cplex since version 12.6.1. More generally, we argue that aggressive bound tightening is often overlooked in MIP, while it represents a significant building block for enhancing MIP technology when indicator constraints and disjunctive terms are present.